Guide · Central heating
Replacing a radiator can be a quick swap or a surprisingly involved job, and the difference is mostly hidden behind the old one. This guide walks through the questions that decide how much work, and so how much cost, is involved.
The reason for replacing a radiator shapes the job. If it is leaking from a pinhole in the panel, it needs to go. If it is cold at the bottom, it may be sludge that a clean would clear. If the room is never warm, the radiator may simply be too small. And sometimes it is just about looks.
Knowing the reason helps you avoid paying for a new radiator when a smaller fix would do, and makes sure the new one actually solves the problem.
Pipe centres are the distance between the two pipes coming up from the floor or out of the wall. If the new radiator has the same centres as the old one, it can usually be connected with new valves and very little pipework. That is the simplest and cheapest kind of radiator replacement.
Older radiators were often made to imperial sizes that do not match modern metric radiators exactly. In that case, the pipes need adjusting or an adaptor is needed. Measure the old radiator from the centre of one valve to the centre of the other before you buy.
Moving a radiator to another wall, or fitting a much wider or narrower one, means extending or rerouting the pipes. Under timber floors this is fairly straightforward. Under solid floors, pipes may need to be surface-run or chased into the wall, which adds time and making good. Our radiator installation page covers sizing radiators for the room.
The radiator itself varies a lot in price:
It is good practice to fit new valves when a radiator is replaced, so old, stiff valves are not left as the weak point. Thermostatic radiator valves let you control each room separately. Our radiator valve replacement page explains valves on their own if that is all you need.
Swapping a single radiator can sometimes be done without draining the whole system, by isolating it with its valves. Replacing several, or replacing valves that will not shut off, usually means draining down. That takes longer and is the natural point to add fresh inhibitor before refilling.
Replacing several radiators on one visit is generally better value per radiator than doing them one at a time, because the draining, refilling and setting up only happens once. If you are thinking about upgrading most of the house, our central heating installation cost guide may be more relevant.
Plasterboard walls need suitable fixings for heavy radiators, and a tall or column radiator may need a fixing into solid timber or masonry. Furniture, fitted kitchens and tight alcoves can all make access harder. Decorating behind the new radiator is usually easiest before it goes up.
When you get a quote, check whether it includes new valves, draining and refilling, inhibitor, any pipework alterations, removing the old radiator and balancing the system afterwards. Clear answers make quotes easy to compare.
Send a photo of the old radiator, its width and height, and the pipe centre measurement if you have it. Call or WhatsApp 07429 632804, or use the quote form. See our central heating page for the rest of our heating work.
Common questions
Clear answers before you arrange a visit.
It depends on whether the pipe centres match, the type of radiator, whether the pipes need moving and how many radiators are being replaced. Chris will give you a clear figure after seeing the job.
Usually, yes. A like-for-like swap with matching pipe centres needs very little pipework.
Not always for a single radiator, if its valves isolate properly. Replacing several radiators or seized valves usually means draining down.
It is good practice, as old valves are often stiff or weeping. New thermostatic valves also give better control of each room.
Often. Air, sludge, stuck valves and poor balancing are all common causes and can usually be fixed without a new radiator.
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